LONG-TERM CHOLESTEROL-LOWERING EFFECTS OF 4 FAT-RESTRICTED DIETS IN HYPERCHOLESTEROLEMIC AND COMBINED HYPERLIPIDEMIC MEN - THE DIETARY ALTERNATIVES STUDY

Context.-The long-term effect of aggressively vs moderately fat-restri cted diets has not been studied extensively in free-living subjects wi th different types of hyperlipidemia. Objective.-To compare the choles terol-lowering effects of 4 levels of dietary fat intake restriction a fter 1 year, Design.-Randomized, parallel, comparison trial. Setting.- Male employees of a large industry. Participants.-A total of 444 men h ad low-density lipoprotein cholesterol (LDL-C) levels above the 75th a ge-specific percentile, Subjects with triglyceride (TG) levels less th an the 75th age-specific percentile were defined as hypercholesterolem ic (HC) and those with TG levels at or above the 75th age-specific per centile were defined as combined hyperlipidemic (CHL). Interventions.- Hypercholesterolemic subjects were randomized to diets 1, 2, 3, and 4 taught to contain 30%, 26%, 22%, and 18% fat, and the CHL subjects wer e randomized to diets 1, 2, and 3, All 4 diets were taught to subjects and spouses or partners in a weekly 2-hour classes. Main Outcome Meas ures.-Plasma lipoprotein levels after 1 year. Results.-Fat intake afte r 1 year declined from a mean of 34% to 36% of energy to 27%, 26%, 25% , and 22% in the 4 HC diet groups and 28%, 26%, and 25% in the 3 CHL d iet groups. Mean+/-SD percent LDL-C reductions were 5.3%+16.2%, 13.4%/-12.6%, 8.4%+/-11.2%, and 13.0%+/-15.7% in the HC diet groups and 7.0 %+/-16.2%, 2.8%+/-15.8%, and 4.6%+/-13.5% in the CHL diet groups (P<.0 1 in all but 1 instance). Apoprotein B levels decreased 8.6%, 10.7%, 4 .3%, and 5.3% in the HC groups and 14.6%, 11.4%, and 9.9% in the CHL g roups(P<.05-.01 in each instance). Triglyceride levels increased signi ficantly in subjects following HC diets 3 and 4, 21.7% and 38.7% (P<.0 5 and .01), but not in any CHL subjects. High-density lipoprotein chol esterol decreased 2.8% and 3.2% in subjects on HC diets 3 and 4, respe ctively (P<.05 in both cases). Conclusions.-After 1 year, moderate res triction of dietary fat intake attains meaningful and sustained LDL-C reductions in HC subjects and apoprotein B reductions in both HC and C HL subjects. More extreme restriction of fat intake offers little furt her advantage in HC or CHL subjects and potentially undesirable effect s in HC subjects.